1. Field of the Invention
This invention relates to a novel compound useful as a herbicide for agriculture and horticulture, to a herbicidal composition containing the same, and to methods of controlling weeds and production thereof.
2. Description of the Prior Art
In recent years, a number of herbicides have been developed and put into practical use. These herbicides have contributed to a saving of labor and an increased production in agriculture. However, there is still room for improvement, and novel chemicals which have reduced effects on useful cultivated plants but have a strong herbicidal action on undesirable plants and which are very safe in regard to environmental pollution have been desired. For example, phenoxyalkanecarboxylic acids represented by 2,4-dichlorophenoxyacetic acid, which have been known for a long time, have superior controlling effects on broad-leafed weeds and still find widespread use. However, since phenoxyalkanecarboxylic acids have only a slight activity on gramineous weeds which are the main noxious weeds, and are phytotoxic to broad-leafed plants which embrace many crops and cultivated trees, these chemicals have only a limited application. Diphenyl ethers represented by 2,4-dichloro-4'-nitrodiphenyl ether have recently gained wide acceptance, but their property of selectivity exterminating noxious weeds is not sufficient. The 4-phenoxy-phenoxyalkanecarboxylic acids proposed recently in West German Patent Application No. P2223894/1972 exhibit some degree of improvement in selectivity, but suffer from the defect that their herbicidal activity is not sufficient.